I do have a strategy for always winning rock-paper-scissors.
Play often for unimportant reasons, and always choose "rock". Now that your adversaries are conditioned to expect you to choose "rock", when an important decision is being decided choose "scissors".
I wonder if there are any reliable techniques for generating good random/pseudorandom numbers mentally. I guess you could just run the same algorithm computers do but it would probably be kinda taxing.
I wonder if a system that uses some arbitrary features of what you can currently see in front of you would be unpredictable enough?
Play often for unimportant reasons, and always choose "rock". Now that your adversaries are conditioned to expect you to choose "rock", when an important decision is being decided choose "scissors".